However, Aubameyang is emerging as a serious alternative as talks continue to stall over a fresh deal at Emirates Stadium.
In January, the Gabon forward publicly hit out at transfer speculation linking him with a move away from the club but his deal is set to expire next summer and preliminary talks did not yield anything meaningful.
In an attempt to avoid a repeat of previous cases where players have run down their deals and left on free transfers -- Aaron Ramsey's move to Juventus last year being the most recent high-profile example -- Arsenal have adopted a policy of aiming to sell players with 12 months left on their deals who refuse to commit.
Aubameyang, who was made captain after Granit Xhaka was stripped of the armband in November, has not agitated to leave and there are hopes within the club the 30-year-old will commit his future to Arsenal when detailed talks are held.
Arsenal were due to sit down with Aubameyang's representatives and his family at the end of the season but the coronavirus pandemic has led to a delay and rival clubs believe there is a growing possibility he could be made available for transfer, especially if the club need to finance a rebuild to help Mikel Arteta overhaul his Arsenal squad.
It is unclear at this stage whether Arsenal would sanction selling Aubameyang to a domestic rival in these circumstances. This would be the biggest stumbling block for Chelsea, who view buying Aubameyang as a cheaper alternative to Dembele or Werner. The latter is most likely to join Liverpool if he leaves Germany.
Lyon would start any negotiations for Dembele demanding a fee of around £70 million whereas the short time left on Aubameyang's contract means Arsenal would be unable to demand a similar fee, perhaps £40m-£50m although all valuations are uncertain with the market in a state of flux.
Aubameyang is seven years older than Dembele but he was in excellent goalscoring form prior to the suspension of English football, sitting second in the League's top goalscoring chart with 17, two behind Leicester's Jamie Vardy.
However, Aubameyang would almost certainly command a higher wage given he already earns close to £200,000-a-week at Arsenal while Dembele is reportedly on £80,000-a-week in France.
Chelsea planned to invest heavily in their squad prior to the pandemic. The financial impact of Covid-19 has forced several Premier League sides to negotiate wage cuts or deferrals -- the Blues are close to agreeing a 10% cut with their first-team players -- while also prompting a review of their transfer plans.
For example, Chelsea retain an interest in Jadon Sancho but his £120m asking price is now a concern in the current climate and in any case, senior figures at the club believe Manchester United are leading the race for the 20-year-old England international.
Olivier Giroud is set to depart on a free transfer at the end of the season while Michy Batshuayi is likely to be deemed surplus to requirements, leaving 22-year-old Tammy Abraham as Chelsea's only recognised forward.